Near the end of production of the Model S Hercules gas engines
in 1929, several changes were made to the basic engine block and
its mechanical features. The pictures shown here are of a 1-3/4 HP
Model S Hercules engine with a June 1, 1929, casting date on the
block and serial number 374563 on the tag. This engine was
purchased in the fall of 1929 by my grandfather, Jacob Karch,
through his son-in-law (my uncle), Harold Miller, who was employed
at the time by Servel, Inc., the parent company of Hercules
Products.
At that time, only one 3-1/4-inch bore style of block was being
cast, all Hercules, Jaeger and ARCO engines of that size using the
same block casting. Model S Economy engines were no longer being
produced, as Sears had opted to sell the newer style Model XK
Economy engines through their catalogs starting in 1928.
Photo #1 shows a few interesting modifications. Close inspection
reveals a 3/8-inch threaded hole just below the end of the detent
blade. This is where the fuel spout brace attached on the 2 HP
Jaeger brand engines. The oblong hole below the detent mechanism is
where the governor arm on the throttling-governed Model SK Hercules
engines went through to attach to the rod to the fuel mixer. The
other feature is the two, longheaded bolts that hold the governor
mechanism to the side of the block. Gone are the awkward-to-reach,
slot-head screws that hid behind the flywheel rim on earlier
engines. These newer bolts permitted the use of a 1/2-inch open-end
wrench instead of an ill-fitting screwdriver. Additional clearances
were made in the detent casting to allow enough room for the bolt
heads.
Photo #2 shows a reversible wear plate that fit in between the
governor bracket and the side of the block. It is about 1/16-inch
thick, and I assume that material had to be machined off the block
where the governor mounts to accommodate the thickness of the wear
plate. Before the use of this plate, the side rod would wear a
groove directly into the side of the engine block surface, causing
the side rod to gradually twist out of the correct position.
Photo #3 shows the rear of the crankcase area, and a notch that
has been machined in the lip to allow accumulated oil to run out of
the back of the base. The notch allowed excess oil to run out onto
the ground instead of forming a puddle under the crankshaft.
Photo #4 shows the Hercules crank guard with a corresponding
notch machined into the lower lip to match up with the crankcase
slot.
Hercules had been making engines of very similar design for 15
years by the time these modifications came about, and why Hercules
waited until the end of production to make these changes is a
curious point.
Glenn Karch is a noted authority on Hercules engines.
Contact him at: 20601 Old State Rd., Haubstadt, IN 47639, or e-mail
at: glenn.karch@gte.net
